Synthetic biomolecular condensates from the co-transcriptional folding and assembly of de-novo designed RNA nanostructures

Biomolecular condensates are integral components of living cells, and synthetically replicating their assembly could help unravelling the mechanisms leading to observed structures and functionalities. Synthetic condensates are equally valuable technological platforms for bioengineering, synthetic biology and synthetic cell science. I will discuss a new strategy for generating synthetic condensates from de-novo designed RNA nanostructures - nanostars - which can be encoded in synthetic DNA genes and expressed in vitro, in synthetic cells or in biological cells [1]. The nanostars have programmable size and valency, and interact selectively through base pairing, enabling control over affinity and the expression of orthogonal condensates that do not mix. Including linker elements mediating affinity between otherwise orthogonal nanostars produces multiphase condensates with programmable degrees of inter-phase mixing [1]. I will demonstrate that, in these structures, the observed morphologies are a consequence of the nonequilibrium co-transcriptional assembly, and differ from the thermodynamic ground state [2]. I will then show that localising enzymes within target sub-domains enables control over the activity of enzymatic cascades [3]. Finally I will discuss expression of the synthetic RNA condensates in E. coli [4].